1. Field of the Invention
The invention relates to a rack shaft support device that supports a rack shaft with the use of a support yoke, and a steering system including the rack shaft support device.
2. Description of Related Art
The configuration of a steering system described in Japanese Patent Application Publication No. 2010-36610 (IP 2010-36610 A) will be described with reference to FIG. 9. The steering system 400 includes a rack housing 410, a rack shaft 420, a pinion shaft 430 and a rack shaft support device 440. The rack shaft support device 440 includes a support yoke 450, a plug 460, an intermediate cam component 470, a rotation force generating spring 480 and an adjusting bolt 490.
The plug 460 has a plug fixing portion 461, a plug internal space 462 and a cam face 463. The plug fixing portion 461 of the plug 460 is fixed to the rack housing 410. The plug internal space 462 of the plug 460 accommodates part of the adjusting bolt 490, the rotation force generating spring 480 and part of the intermediate can component 470.
The intermediate cam component 470 has a spring retaining portion 471, a restricting portion 472 and a cam face 473. The cam face 473 of the intermediate cam component 470 contacts the cam face 463 of the plug 460.
The restricting portion 472 functions as a guide at the time when the plug 460 and the intermediate cam component 470 are assembled to each other and functions to restrict relative radial movement of the mutually assembled plug 460 and intermediate cam component 470. The restricting portion 472 has a first restricting portion 472A arranged inside the plug fixing portion 461 and a second restricting portion 472B arranged outside the plug fixing portion 461. The restricting portion 472 restricts radial movement of the intermediate cam component 470 with respect to the plug 460 by the contact of the outer face of the first restricting portion 472A with the inner face of the plug fixing portion 461.
The spring retaining portion 471 retains the rotation force generating spring 480. The spring retaining portion 471 is formed at a plug 460-side end portion of the first restricting portion 472A. The spring retaining portion 471 has two columnar portions extending toward the plug 460 and a groove formed between the two columnar portions.
The rotation force generating spring 480 has a first spring end portion 481, a second spring end portion 482 and a spring winding portion 483. The first spring end portion 481 is connected to a spring retaining portion 491 of the adjusting bolt 490. The second spring end portion 482 is connected to the groove of the spring retaining portion 471 of the intermediate cam component 470. The rotation force generating spring 480 applies force to the intermediate cam component 470 to cause the intermediate cam component 470 to rotate with respect to the plug 460.
The rack shaft support device 440 has such a configuration that an intermediate cam component 470-side portion of the plug internal space 462 is filled with the first restricting portion 472A. Therefore, the rotation force generating spring 480 is required to be arranged on the plug 460 side in accordance with the size of the first restricting portion 472A in a pressing direction. Therefore, there is a possibility that the plug internal space 462 needs to be increased. In addition, the rack shaft support device 440 has the adjusting bolt 490, so it is difficult to reduce the size in the pressing direction.